docs: def le(self, other):
          """
          Less than or overlaps. Returns True if no part of this Interval
          extends higher than other.
          :raises ValueError: if either self or other is a null Interval
          :param other: Interval or point
          :return: True or False
          :rtype: bool
          """
          self._raise_if_null(other)
          return self.end <= getattr(other, 'end', other)